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cAnaconda Reduction 

Works 



OCTOBER 1919 



Copyright 1919 
by the 

cylNACONDA COPPER cTWINING COMPANY 

A, cANACONDA, cTVIONTANA 

' 1 .- 







I 


Anaconda and the Upper in 1887 













A Brief Description of the 

Anaconda Reduction Works 

^ ^ 

i^ROM P ION HER DAYS TO iqtcj 

OR THIRTY yp:ars the Butte mines have annually 
yielded more copper than any other single district 
in the world, and since 1910 there has been an 
increasingly large production of zinc. During the 
last quarter of a century most of the world’s silver 
has come as a liy-product of co])per and lead smelt¬ 
ing; and for many years Butte has been one of the foremost 
sources of this metal. A\diile the war was in jirogress, con¬ 
siderable manganese ore was shipped for use in making steel. 

The first mining shafts were sunk .in silver ore; but 
after going through two or three hundred feet of oxidized 
ground the deposits were found to he rich in copper, and silver 
became of secondary importance. From that time forward 
the Anaconda Cojiper Mining Company has been the chief 
producer in the district; and its eijuipment has necessarily 
corres]ionded to its output. In the first two years of active 
copper mining,- from 1882 to 1884, thirty-seven thousand tons 
of ore averaging forty-five per cent copper was shipped to 
Wales by this Company. The city of Swansea, in Wales, had 
been the world’s principal center of cop])er smelting, and in the 
early eighties it still held an important place, though its busi¬ 
ness in this line was declining. In September 1884 the Com¬ 
pany began treatment of its ore locally, in a plant that handled 
five hundred tons in twenty-four hours, and this made it 
unnecessary to continue selecting the very rich portions. The 
ore sent to the Works for the first few years had an average 

Page Five 







copper content of twelve per cent. This was mechanically con 
centrated and then smelted into matte, the latter containing 
sixty-four per cent copper. The matte was sent to Swansea, 
and to Baltimore, for several years; but in 1892 a full installa¬ 
tion of converters was provided to treat it, and since then 
nothing but metallic copper lias been shipped. The size and 
capacity of plant have steadily increased with the growing- 
demand for the red metal; and economies in production have 
permitted the handling of lower and lower grade ores. Those 
that are now treated contain three per cent copper, which is 
less than in some of the waste products of the original plant. 
The present daily capacity is seventeen thousand tons of ore, 
or thirty-four times as much as in 1884; and the growth has 
been fairly regular through all these years. 

An abundant supply of commercially important minerals, 
combined with skilful development of mining, metallurgical 
and business operations, has made the Anaconda Reduction 
Works the largest in the world among establishments pro¬ 
ducing any of the metals except iron and steel. During the 
past five years the output has been sixteen per cent of the 
copper produced in the United States, and more than nine 
per cent of the world’s production. The remarkable ex¬ 
pansion of the Company’s operations is closely related to the 
marvelous growth of the electrical industries, which consume 
enormous quantities of copper. 

The works were located at Anaconda, twenty-six miles 
from the Butte mines, because there was no adequate water 
supply at any nearer point. The first plant was built on 
the north side of Warm Springs valley ; the present one, which 
began operations in February 1902, is on the south side of 
the valley, and is situated a mile east of the residential limits, 
on a hill-slope. Such a site, suitably graded for inter¬ 
department transportation, leads to great simplicity and con¬ 
venience in the movement of all materials. 


f 


Page Six 


THE ORES 

HERE ARE THREE types of oi'c ill the Butte mines, 
the first lieing chiefly valuable for its copper, the 
second for zinc, and the last for manganese. The 
main or central zone, which supplies three- 
quarters of the cop])er ore, has been the jirincipal 
scene of mining operations in the district; but dur¬ 
ing the past nine years there has been increased activity in 
the intermediate zone, which surrounds the central area, and 
which is the source of most of the zinc ore. Mining for zinc 
has, indeed, been the main cause of this new activity. The 
intermediate zone also supplies a certain amount of copper 
ore; and manganese minerals begin to appear here. The 
presence of a good deal of manganese in the third or outer 
zone has long been known; but not until 1918 did market 
conditions favor the mining of manganese ore. Zinc is also 
imi)ortant in this zone, but copper is very scarce. 

The two principal copper minerals are chalcocite or 
glance (a sulphide of copper) and enargite (copper-arsenic 
sulphide), associated with pyrite (iron sulphide) in a gangue 
of quartz and altered granite. Bornite (a copper-iron sul¬ 
phide) is present in small amounts; and covellite, the beau¬ 
tiful indigo-colored copper sulphide, is found but is not com¬ 
mon. Ore is frequently mined that has the appearance of 
being mostly pyrite but which contains the above named 
co])per minerals in finely distributed particles. Silver occurs 
in the central zone in the proportion of six-tenths of an ounce 
per ton for each per cent of copper; but the relatively small 
quantity of copper ore taken from the intermediate zone 
carries double this proportion of silver. Gold occurs only to 
the value of fifteen cents per ton of ore, but this is of 
some consequence considering the enormous tonnage treated. 
The relative importance of copper, silver and gold is exactly 
the reverse of what it was in Montana’s pioneer days, when 
the miners were in search of gold, gave less attention to silver 
and took no interest in copper. These facts, which corres¬ 
pond to the history of other mining regions, justify the proverb 



Page Seven 



that ‘‘a man is likely to go to the poor house with a gold mine 
on his hands, may make a fair living from a silver mine, but 
easily becomes wealthy when he finds a good copper mine.” 

Zinc occurs as sphalerite (the sulphide) associated with 
pyrite, rhodonite (manganese silicate) and rhodochrosite 
(the delicate pink manganese carbonate). These ores contain 
four-tenths of an ounce of silver per ton for each per cent of 
zinc. Galena, the sulphide of lead, is found very sparingly. 

The manganese is mostly in the form of rhodochrosite, 
hut the oxide, pyrolusite, has also been mined in small 
quantities. There is a great deal of rhodonite in the outside 
zone, but this has not been mined because it is not acceptable 
to the steel makers. From this zone small quantities of silver 
ore are shipped, containing from ten to thirty ounces of silver 
per ton. 

The various minerals that have been named are asso¬ 
ciated with much larger quantities of quartz and altered 
granite. Indeed, two-thirds of the material taken from the 
central zone is altered granite which, however, contains enough 
of the copper minerals in seams and veinlets to constitute ore. 
The ore from the intermediate zone contains forty per cent 
granite, with less pyrite but more quartz than occurs in the 
central area. The gangue in the outer zone is nearly all 
quartz. 

In addition to the ores from Butte, small shipments are 
received from other places, principally from the Southern 
Cross mine at Georgetown. These shipments consist chiefly 
of the iron oxides (limonite, hematite, siderite and magnetite), 
with small amounts of quartz and limestone. This ore is used 
as a flux in smelting, and also contains considerable value in 
gold. 


Page Eight 



Three Thousand Tons of Ore, and a Train Butte, Anaconda and Pacific Railroa^, Crossing 

of Box Cars, Hauled b}) Electric Locomotives the Milwaukee and the Northern Pacific Roads 





















Florv of Material from Ore Cars to Copper Cars 















































































































OUTLINE OF PROCESSES 


HE coppEf'i ORES^ delivered on the “high line” l)y the 
Butte, Anaconda and Pacific railway, are first 
enriched bv mechanical concentration. In this 
process the useless part of the ore is separated from 
the valuable portion by making use of differences 
in specific gravity, the useless part being sluiced to 
the dump and the three per cent of copper in the ore becoming 
eight per cent in the concentrated product. 

The product, which has been reduced to three-eighths of 
an inch and less in diameter, is roasted, to remove eighty 
])er cent of its sulphur, and is then smelted in reverberatory 
furnaces. When an extra large production of copper is called 
for, some of the ore, left in a coarser condition, is smelted in 
blast furnaces, in which the burning off of sixty per cent of 
the sulphur and the melting of the charge are done in one 
operation. The reverberatories and blast furnaces produce 
matte with an assay of about forty per cent copper, and 
make slag as a waste product which is sluiced to the dump. 
The matte is treated in converters, which deliver an impure 
copper. The last stage is reached in the refining furnaces, 
which turn out the commercially pure metal; and this is 
shipped to the Company’s electrolytic plants at Great Falls, 
Montana, and Perth Amboy, New Jersey, where the silver 
and the small amount of gold are separated. The metals are 
then marketed. 

The zinc ore is increased from an assay of twelve per 
cent zinc to thirty-two per cent by mechanical concentration. 
The metallurgical treatment of this concentrate is conducted 
at the Company’s plant in Great Falls, except as noted under 
the subject of roasting. 



Page Eleven 
















COFFER CON CENTRA TOR 


ms DEPARTMENT coiitaiiis eight independent sec¬ 
tions, each of which treats nearly twenty-one hun¬ 
dred tons of ore in twenty-four hours. One of 
these sections is here described. 

The valuable minerals are separated in several 
stages; as much being taken out in the first stage 
as can be obtained of high enough value. The remaining part 
of the ore is then further crushed, to release the enclosed valu¬ 
able minerals, and these in turn are separated as part of the 
concentrated product. 

The ore as received from the mines ranges from fifteen 
inches in diameter to dust. The process begins by delivering 
the ore from the bin to a 12 by 24-inch Blake crusher, through 
two shaking feeders. The bottom plate of each feeder is 
perforated with two-inch round holes, through which some 
of the finer part of the ore drops, thus lessening the load on 
the crusher. The ore broken by the crusher passes to two 
trommels or revolving screens. These deliver the sizes that 
are still coarser than two inches to two 8 by 20-inch crushers 
for further reduction in size, while the finer portion joins 
the undersize from the shaking feeders. All of the ore, 
now reduced to two inches and smaller, is raised to the top 
of the mill by bucket elevators, and is divided by a series of 
trommels for jigging, and a final undersize for other treat¬ 
ment. When the blast furnace department is in operation, 
the first two sizes, from two inches to three-eighths inch, are 
treated in water on Harz jigs, making concentrate, which is 
sent to the blast furnaces, and middling. The middling is 
ground finer in two sets of rolls, and sent back to the trommel 
system by way of the above mentioned elevators. When 
the blast furnaces are not in use, all of the two-inch to three- 
eighths inch ore is simply ])assed on through the rolls and 
the finer trommels and is treated on the machines farther on. 
The two sizes from three-eighths inch to one-sixteenth inch, 
are treated on Evans jigs, which also make concentrate and 
middling. This middling is ground to one-sixteenth inch and 
finer in rolls, and goes, together with that part of the original 



Page Thirteen 



Evans Jigs 
























Hardinge Mills 





























material that is finer than one-sixteenth inch, to Anaconda 
classifiers. In these, a rising current of fresh water causes 
the slime to overflow, while the sand discharges from the 
spigots and passes to Wilfley tables. Here a further portion 
of concentrate is obtained, and the middling which remains 
is sent to Hardinge ball mills for still finer grinding. Each 
mill discharges the finely ground sand into a Dorr mechanical 
classifier. The latter sends back to the mill the portion that 
is not yet fine enough, while sizes from two one-hundredths 
of an inch to slime pass to the flotation machines. Here is 
the first point at which a waste product is made, tailing- 
being washed to the dump from the flotation machines while 
another portion of concentrate is saved for smelting. 

The slime that overflows from the classifiers preceding 
the Wilfley tables consists of three per cent solid matter with 
ninety-seven per cent of water, and is thickened to fourteen 
per cent solids in circular tanks twenty-eight feet in diameter 
and three feet deep, placed in another building. Part of this 
thickened slime is returned to the main building for admix¬ 
ture with the finely ground sand as the latter enters the 
flotation machines, the proportions of sand to slime being 
eleven to one. The remainder of the thickened slime is 
treated in another set of flotation machines in a special build¬ 
ing. Here the final recovery of concentrate is made, and 
more tailing is sent to the dump. 

It is of interest to compare the three different methods 
by which concentrate is separated from the ore. In each 
jig a plunger produces rapid upward pulsations of water 
through the bed of ore that rests on the sieve. These pulsa¬ 
tions make the bed just loose enough for the valuable minerals 
to settle below the other parts of the ore, on account of their 
greater specific gravity. The layer of concentrate passes out 
through an adjustable trapped gate, while the middling flows 
over the end of the jig. The Wilfley tables move the thin bed 
of ore forward as the result of a peculiar jerk imparted by 
the driving mechanism; but the concentrate moves with 
greater momentum than the middling, due to its greater 
specific gravity. The shaking action slightly loosens the bed 
of ore, so that the concentrate settles below the middling. 

Page Sixteen 


The wash water, flowing across the table at right angles to 
the direction of the jerking motion, carries the middling over 
the lower edge of the table while the riffles guide the con¬ 
centrate to the end of the table. In the flotation machine we 
have what may be aptly called an up-side-down process: the 
specifically heavier minerals are made to rise in a mass of 
water while the lighter minerals sink. This is brought about 
by taking advantage of the fact that, when certain oils are 
mixed with the ore, thev stick to the metallic minerals but 
do not attach themselves to the non-metallic minerals. 
This selective action is aided by the use of small quantities 
of sulphuric acid. Vb'gorous agitation of the mixture of water, 
ore and oil beats air into the mass ; and the presence of the 
oil makes a persistent froth of air l)ubbles, so light that it can 
support the fine mineral particles that adhere to the oil. The 
success of the flotation process depends on grinding the ore so 
fine that a considerable proportion of it is slimed or, in other 
words, reduced to the almost impalpable condition of clay. 
Particles even as fine as three one-thousandths of an inch in 
diameter give no satisfactory results unless mixed with the 
much finer, slimed ore. 

The water is easily removed from the coarse sizes of 
concentrate l)y means of short stationary screens. From the 
medium sizes the excess water is gotten rid of in large 
settling tanks. The extremely fine, flotation concentrate also 
goes to settling tanks; but the settled product still contains 
forty per cent of water. This is reduced to fifteen per cent 
by ineans of Oliver continuous filters, which are large revolv¬ 
ing cylinders operating in steel tanks. 

In the concentrator, ninety-five per cent of the copper is 
saved by these relatively cheap processes, while nearly tw'o- 
thirds of the ore is discarded. Previous to the introduction 
of flotation the recovery was low, for two reasons: earlier 
practice did not carry the fine grinding far enough to release 
all of the copper-bearing mineral, some of the tailing going 
to the dump in sizes as coarse as six one-hundredths of an 
inch, which is three times the diameter of the coarsest particles 
now sent to waste; and the methods then in use for concen¬ 
trating the very fine sizes w^ere much less efficient than flota¬ 
tion. Page Seventeen 



Flotation Machines 











ZINC COXCEXTRATOR 


HE zixc COXCEXTRATOR has a capacity for treating 
twenty-one hundred tons of ore in twenty-four 
hours. The preliminary breaking is done by 
stages, in an equipment of crushers and rolls much 
the same as is used in the copper concentrator. 
Between stages the ore that is already fine enough 
is screened out. The final grinding is done in ball mills which 
operate in circuit with mechanical classifiers; and all of the 
ore is finally ground to such an extent that the size of par¬ 
ticles rangfes from a maximum of fifteen one-thousandths 
of an inch down to the extreme fineness of clay. The actual 
concentration is all done by the flotation method. 

Bv concentration, two-thirds of the ore is discarded to 
waste, while the concentrate is skimmed off and is settled out 
of the water in large tanks. From these tanks it goes to the 
automatic filters, which leave eight per cent moisture. After 
removing this moisture, the concentrate contains thirty-two 
per cent zinc, and also fifteen ounces of silver per ton. The 
recoverv is ninetv-two per cent from ore that averages twelve 
per cent zinc. 

Some of this concentrate is roasted before shipping; but 
most of it goes direct to the Company's Great Falls plant, 
where the highest grade of zinc is produced. 



Paiie Xincteeii 





Leaching Tanias, Showing 
Feed Distributors 





























LEACHING PI.ANT 


REVious TO ADOPTING the flotation process of con¬ 
centration, the tailing that was sent to the dump 
from the New Works concentrator carried an aver¬ 
age of thirteen pounds of copper per ton,'which is 
three times as much as is contained in the tailino- 
that is produced now. Exposure to the weather 
and to the action of a small amount of carbonate of lime in the 
water continually running over the dump has converted 
ten or fifteen per cent of this copper from sulphide to car¬ 
bonate. The carbonate is difficult to recover by mechanical 
concentration, but is very easily soluble in acids. One of the 
recent improvements at the plant is the re-treatment of this 
old tailing by dissolving the contained copper in sulphuric 
acid. 

By means of an electrically operated excavator this old 
material is loaded into fifty-ton bottom-dump cars and is 
transferred to large storage bins at the leaching plant. From 
these bins the material is distributed to roasting furnaces, in 
which the sulphide of copper is converted into oxide. These 
furnaces are described in the section on roasting. Their prod¬ 
uct is passed through rotary coolers to a mixer, where a little 
water is added to lay the dust; after which the material is de¬ 
livered to immense leaching tanks by a series of rubber belt 
conveyors. The purpose in cooling the roasted material is 
to prevent rapid destruction of these belts. 

The leaching ecpiipment consists of fifteen redwood 
tanks, each fifty feet in diameter and fourteen feet deep, to¬ 
gether with coils for heating, and pumps for circulating, the 
solutions. Five of the tanks are simply for storage of solu¬ 
tions, while the other ten are used for the actual extraction 
of the metal. These ten are lead lined. Cocoa matting is laid 
on the bottom, through which the solutions are filtered after 
they have dissolved the copper from the sand; and the matting 
is protected against excessive wear by wooden gratings laid 
over it. 

A tank receives a thousand tons of roasted charge, which 

Page Twenty-one 






is distributed by a simple inclined movable chute, along* the 
bottom of which there are several adjustable gates. The 
leaching is done by downward percolation of hot solutions 
containing sulphuric acid and salt. The main ])urpose of the 
salt is to dissolve silver, which would not be taken up by the 
acid alone; but the salt also increases the speed of extraction 
of the copper. For each thousand-ton charge of sand there 
are used seventy thousand gallons of fresh water, thirty-five 
tons of commercial sulphuric acid and fifteen tons of common 
salt. The first liquor to be passed through a fresh charge of 
sand has already been used on previous charges, this being 
the standard method, in all such processes, in order to dissolve 
the maximum amount of metal in the minimum quantity of 
solution. After a suitable period of contact this first liquor 
is drawn off as the “strong solution"' from which copper and 
silver are later precipitated. This solution is followed by 
others, successively weaker in copper, and finally by the fresh 
water. The spent charge is sluiced out of the tank through 
bottom gates, with water that has previously been used in 
the concentrator. This re-use of water is a necessarv measure 

w' 

of economy which is practiced at various points about the 
Works. The total time required to charge, leach and dis¬ 
charge a tank is four and a half days. 

Certain oxidized ores of copper are also leached. They 
do not need roasting, and have to be crushed onlv enough to 
make everything pass through a one-inch hole. 

The copper and silver are recovered from the strong 
solution by passing the latter through a mass of scrap iron 
in a series of concrete tanks. The iron displaces the copper 
from solution and is itself largely dissolved, though part of 
the iron rusts and remains as rust with the so-called cement- 
or ])recipitated copper. This final product is dried and, as 
it then contains only sixty per cent copper, is smelted in the 
reverberatory furnaces, which are described later. 


Page Twenty-two 


ROASTING 


OASTiNG, in metallurgy, consists in burning the 
sulphide minerals to get rid of sulphur and to leave 
more or less of the metal content as oxides. The 
operation has to be conducted at a good red heat, 
yet below the temperature at which fusion would 
take place. In the case of copper smelting the 
aim is to remove only part of the sulphur, some of it being 
purposely left to form matte in the succeeding treatment; but 
in the case of zinc the sulphur is removed as completely as 
possible. 

All of the roasting furnaces at this plant, whether for 
copper concentrate, zinc concentrate or the old tailing, are 
of the McDougall type. This is a cylindrical furnace, with 
several hearths one above another, substantially built of brick 
and enclosed in a steel plate casing so that there shall be no 
injury to the furnace by expansion and contraction. The 
large amount of brick work absorbs a great deal of heat, 
while the cylindrical form, having less outside surface than 
any other shape, radiates less heat. Under these favorable 
conditions any fine ore that contains a large percentage of 
iron pyrite will roast without the use of other fuel, because 
the pyrite develops more heat than most minerals, its sulphur 
burning to sulphur dioxide gas and its iron to the solid, red¬ 
dish brown oxide. When a furnace is being put into opera¬ 
tion from a cold condition it must, of course, have a prelimi¬ 
nary heating wdth wood or coal. 

In number one roaster building the fine copper concen¬ 
trate, from jigs and tables, is handled in sixty-four furnaces, 
each of which is fifteen feet inside diameter and has six 
hearths. The concentrate, automatically fed to the top hearth, 
is moved from the circumference to the center by two rabble 
arms which are attached to the central shaft, and drops 
through an opening to the next hearth, across which it is 
similarly moved to the circumference. The stirring action of 
the rabbles constantly exposes fresh surfaces of the charge to 
the hot gases, which come up from the lower hearths. These 
gases dry out the eight per cent of moisture from the con- 

Page Twenty-three 






Tops of Roasting Furnaces, with Feed Hoppers Above 































centrate while passing over the top hearth; and before the 
charge has crossed the second hearth it is hot enough to begin 
roasting. The necessary air enters through the open doors 
of the bottom hearth. A dry sample of average feed contains 
thirty-three per cent sulphur, which is reduced to eight per 
cent in the product. The latter is commonly called ‘‘calcine.” 
Each of these furnaces has a capacity of forty-five tons, dry 
weight, of feed per twenty-four hours. 

Number two roaster building serves especially for hand¬ 
ling the flotation concentrate ; but it also receives i)art of the 
table and fine jig products. There are twenty-eight furnaces 
in number two building, each having seven hearths and be¬ 
ing twenty-three feet inside diameter. Each of these furnaces 
handles one hundred and twenty-five tons, dry weight, of 
charge per twenty-four hours. The feed contains twelve per 
cent moisture. The thirty per cent of sulphur that remains 
after drying is reduced to nine per cent by roasting. Since 
the flotation concentrate is excessively fine, special attention 
was given to the detail design of these furnaces, in order to 
minimize the loss by dusting. 

The furnaces in the leaching plant are similar to those 
in number one roaster building; but on account of the small 
percentage of sulphur in the feed, these furnaces receive 
extra heat from carefully regulated coal fires. 

Some time after the zinc plant operations began at Great 
Ealls, more roasting capacity was needed; and it was deemed 
better to use certain furnaces in the roaster building of the 
leaching department, here in Anaconda, than to build extra 
furnaces at Great Falls. For that reason, part of the zinc 
concentrate is roasted at this plant before shipping. This 
product contains too little pyrite for satisfactory self- 
roasting, so that coal fires are necessary. The thirty-two per 
cent sulphur in the feed is reduced to four per cent in the 
product; but three-fourths of this remaining sulphur is in the 
form of sulphate, which is readily soluble in the subsec|uent 
leaching process. 

In all of these roasting furnaces the heat would warp 
the cast-iron rabble arms if suitable provision were not made 


Page Twenty-five 


for cooling. The arms are hollow, and water continually 
circulates through them, except in the case of the furnaces 
used to roast the old tailing. Air cooling is sufficient in that 
instance; and in cold weather the hot air from this source sup¬ 
plies most of the heat for the large building that contains the 
leaching tanks. 

m m m 

REVERBERATORY SMELTING 

HE PRINCIPAL PART of a I'cverberatory furnace is 
a large chamber built of silica brick and thorough¬ 
ly braced with steel buckstays. The material to 
be smelted is charged onto the hearth, and the heat 
that is needed to fuse it is received by radiation 
from the incandescent flame of the fuel. Nine- 
tenths of the charge is calcine from the roasting furnaces, the 
rest being mostly dust produced in the various departments 
and caught in the system of chambers and flues that is de¬ 
scribed later. The charge contains a mixture of sulphides and 
oxides of copper and iron, together with silica, alumina and 
lime. A suitable amount of silica and alumina is purposely 
left in the product of the mechanical concentrating process to 
combine, during the smelting operation, with the oxide of iron 
that is produced in roasting. The product of this combina¬ 
tion is slag; and by discarding the latter the copper remains 
in an enriched material—the matte. The lime is added, as 
finely broken limestone, in order to form a more easily fusible 
slag. To mix this lime with the rest of the charge, it is 
included as part of the feed to the roasting furnaces. 

In the fused state copper has greater affinity for sulphur 
than have the other metals; consequently the copper oxide 
that is in the charge reacts with sulphide of iron to form 
copper sulphide, iron oxide and sulphur dioxide. This iron 
oxide, of course, becomes part of the slag and the sulphur 
dioxide passes away with the rest of the gases. Other similar 
reactions also eliminate sulphur, so that four and a half per 
cent of the charge passes into the flue as sulphur dioxide 
and thus disposes of more than a quarter of the sulphur 

Page Twenty-six 







m the smelting mixture. Another three and a half per 
cent of the charge goes off as carbonic acid gas from 
the decomposition of the limerock. The copper sulphide 
and the remaining iron sulphide melt together to form 
the matte, which has a specific gravity twice as high as 
the slag and hence settles to the bottom of the molten 
mass. From each hundred tons of charge, containing 
something over nine per cent of copper, there are produced 
twenty-four tons of matte, containing thirty-eight per cent of 
copper, and sixty-seven tons of slag. The latter runs off con¬ 
tinuously into a stream of water which chills and granulates 
it and then transports it to the dump through a system of 
flumes. The matte is tapped from the furnaces periodically, 
and taken in immense steel ladles to the converters. 

During the past few years reverberatory smelting has 
had marked attention from copper metallurgists, with cor¬ 
responding improvements in practice. These improvements 
have been along three lines: first a continuation of the striking 
increase in size of furnaces that has now been taking place 
for forty years; second in the manner of charging the fur¬ 
naces; and, finally, there has been much betterment in the 
method of using the large quantities of coal that are con¬ 
sumed. 

The present furnaces have hearths twenty feet and four 
inches wide and one hundred and forty-three feet long; and 
the area is sixteen times as great as in the furnaces used by 
the Company in 1884. A hearth of the earlier date could, 
indeed, he put inside of the present structure with its long 
dimension across the width of the new furnace. 

That early plant was laid out in such a way that it was 
necessary to quench the calcine with water before taking it to 
the matte furnaces, in order not to smother the men with 
the sulphur fumes in a blind tunnel into which the calcine was 
dropped from the roasters. This meant both a cold and a wet 
charge for smelting; and required a great deal of extra fuel 
to dry the charge and bring it back to the temperature that 
it had before wetting. At present as little time as possible is 
lost between roasting and smelting, and the charge enters the 


Page Twenty-seven 
































reverberatories at a temperature of eight hundred to nine 
hundred degrees Fahrenheit. In early practice the charge 
was shoveled into the furnace by hand, through side doors; 
but a great deal of cold air was, unfortunately, admitted at 
the same time. The present method is to drop the charge, by 
gravity, from overhead hoppers through iron pipes which are 
built into the roof of the furnace. This method admits but 
little cold air, requires far less time and less hard, disagree¬ 
able work, and permits heaping the charge against the sides 
of the furnace, thus protecting the walls and also exposing 
a larger surface of material to absorb the heat. 

Until a few years ago the coal was used in the time- 
honored way, on a grate at one end of the furnace; but the 
present standard practice is to grind the coal nearly as fine 
as flour and blow it directly into one end of the hearth with 
an air blast, where it burns like a gas flame, and the products 
of combustion pass away at the other end of the furnace. 
Since, by the new method, the combustion takes place wholly 
in the hearth itself, instead of partly on a grate that is sepa¬ 
rated from the furnace chamber by a bridge-wall, the heat 
is better utilized. Moreover, this method permits a nearly 
perfect control, so that there is a very uniform temperature 
condition and an almost constant quality of flame, which are 
decidedly more efficient than the unavoidably varying flame 
and temperature of the old-style firing. 

All three of these changes have saved a great deal of 
fuel, which is the chief item of expense. Much of the heat 
from the fuel has also been saved in another way, which is 
not strictly a point in reverberatory operation, but rather one 
of general economy. This consists in passing the waste gases 
through a set of steam boilers. On account of the close con¬ 
tact of the gases with the boiler tubes, more heat is saved in 
the steam than is utilized in the smelting, which, as before 
indicated, receives most of its heat by radiation from the 
myriads of incandescent particles in the flame, as the latter 
passes over the charge, and only a little by direct contact. 
Though it would be desirable to utilize a larger part of the 
heat in actual smelting, yet it is seen what striking advance 


Page Twenty-nine 



1 

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B 






■4' 









'^Btin b^^H 


Matte Settlers in Front of Blast Furnaces 








there has been in both efficiency and economy when we state 
that the smelting capacity of a single furnace has increased 
from twenty tons of charge per twenty-four hours, using ten 
or twelve tons of coal, in 1884, to five hundred and fifty tons 
of charge and ninety-two tons of coal in 1919, amounting to 
twenty-seven times the capacity on sixteen times the hearth 
area with only nine times the tonnage of coal. 


BLAST FURNACE SMELTING 

HE BLAST FURNACES are Steel structures fifteen feet 
deep, the inside width varying from four and a 
half feet at the bottom to six feet at the top. 
There are two furnaces each fifteen feet long, one 
that is fifty-one feet long and another eighty-seven 
feet long, inside. The sides are water-jacketed as 
a ])rotection against the intense heat developed by the smelt¬ 
ing operation; and a constant flow of clear water is main¬ 
tained through these jackets. Extending above this steel 
structure is a brick top as a convenience for disposing of the 
waste gases; and this upper portion has vertically sliding- 
doors on each side just above the level of the charge floor, 
operated by means of compressed air. 

Blast furnace smelting is best adapted to ore from a 
quarter of an inch to five or six inches in diameter; though 
more or less material outside of these limits is used. If fine 
material was treated, such as is sent to the reverberatories, 
the strong blast of air that passes through the charge would 
carry a large part of it out of the furnace and cause great 
losses. On the other hand, coarse ore cannot be economically 
treated in reverberatory furnaces, because the smelting would 
be too slow. 

The smelting mixture contains the coarser portion of 
the product from the copper concentrator, coarsely broken 
limerock, some chilled slag that is returned from the convert¬ 
ing process, and miscellaneous clean-up material from other 
departments. This mixture is brought from the stock bins 
in trains of special side-dumping cars. Under the spouts of 

Page Thirty-one 





the various stock bins there are automatic track-scales, an 
arrangement that permits proper proportioning of the differ¬ 
ent materials. When these cars arrive at the furnace they 
are dumped by hooking them up to compressed-air pistons. 
Just before putting each charge into the furnace, through the 
side doors, two hundred pounds of coke per ton of charge 
is introduced from large barrows. Air, supplied by great 
rotary blowers in the power house, at a pressure of forty- 
two ounces per square inch, is forced into the bottom of the 
furnace through numerous tuyere pipes; and, rising through 
the charge, burns the coke and also sixty per cent of the 
sulphur content of the charge. The heat from the burning 
of this sulphur saves a great deal of coke. The most intense 
combustion and the.highest temperature occur just above the 
tuyere level; and, as the gases rise from this zone, a great deal 
of their heat is absorbed by the charge. The more fusible 
materials melt pretty well up in the column and, trickling 
over the refractory portions, flux the latter. It is this action, 
together with the effective contact of the hot gases with the 
charge, that accounts for the greater speed with which coarse 
material smelts in a blast furnace than in a reverberatory. 

The burning of part of the pyrite, or sulphide of iron, 
yields iron oxide which, as in the reverberatory furnaces, 
combines with the silica, alumina and lime to form slag. The 
copper sulphide melts together with that part of the iron sul¬ 
phide that has not been burned, to form matte. The two 
products collect in a shallow pool in the bottom of the furnace 
and flow out through water-jacketed spouts into large set¬ 
tlers. These spouts are so designed that the surface of the 
pool is maintained a little above the holes through which the 
molten mass passes, thus forming a trap to prevent any of 
the air blast escaping at this point. In the settlers the matte 
separates to the bottom, and the slag passes through an over¬ 
flow spout into a stream of water, which granulates it and 
carries it to waste. At suitable intervals the matte is drawn 
off through tap holes and delivered to the converters. 

One of the smallest furnaces treats five hundred tons 
of charge per twenty-four hours, containing eight and a 


Page Thirty-two 


half ])er cent copper, and turns out eighty tons of matte with 
a content of forty to fifty per cent copper, and two hundred 
and seventy tons of slag*. Four per cent of the charge is 
blown out by the air blast, hut most of this is caught in the 
chamber and flue system. Sixty per cent of the total sulphur 
in the charge is burned off, amounting to thirty-three tons. 
Ten ])er cent of the charge is also eliminated in the form of 
the carbonic acid gas that is driven off from the limestone. 

The large furnace has a capacity of twenty-five hundred 
tons of charge per twenty-four hours. 

The new economies effected in reverberatory smelting 
have made it unnecessary to use the blast furnaces except 
when more ore is mined than can be treated in the reverbera- 
tories. 

m m m 


CONVERTING 

F ALL OPERATIONS about the Works the converting 
process is the most spectacular. Flames of vary¬ 
ing color are here seen belching from the throats 
of specially designed tilting furnaces of a pot¬ 
like shape; and, when these are turned down 
to rapidly pour off immense masses of slag or 
copper, there is a suggestion of Othello’s “gulfs of liquid fire.” 

A converter, as used at this plant, is a large cylinder top¬ 
ped with a truncated cone, the cone being open at its upper, 
small, end to receive the charges and as an outlet for the 
gases. It is made with a shell of heavy steel plate, thickly 
lined with magnesia brick. The inside dimensions are sixteen 
feet diameter and fifteen feet deep. At the back and near the 
bottom a line of tuyere pipes admits compressed air. As a 
converter with its charge of matte weighs three hundred 
tons and has to be frequently tilted, the supports are carefully 
designed and very substantially built. These supports are 
two pairs of massive steel rollers carried on equally massive 
foundations. Power for tilting is supplied through a hundred 
horse-power electric motor for each converter. 



Page Thirty-three 




Converters 




























The converting process is the last stage in the series of 
eliminations that finally leave metallic copper. Molten matte 
is brought from the reverberatory and blast furnaces in large 
steel ladles, and poured into the converters—sixty-five tons to 
a charge. Air, at sixteen pounds pressure per square inch, is 
blown through the liquid mass, burning the sulphur and the 
iron. The sulphur dioxide gas passes into the flue, and the iron 
oxide combines with the silica and alumina of the raw ore 
that is added to supply these slag-forming substances. The 
slag is poured off into ladles by tilting the converter; and 
after practically all of the iron has thus been disposed of the 
copper sulphide remains wdth a content of seventy-eight per 
cent copper. Continuation of the blowing burns off all but a 
very little of the remaining sulphur, and the metallic copper 
settles to the bottom alloyed with the silver and gold. This 
is finally poured into ladles and transferred to the refining 
furnaces. The conversion of a sixty-five ton charge of matte 
requires three hours to slag the iron, and another hour and 
three-quarters to finish. The operators judge the stage of 
the process by the size and color of the flame, which changes 
from yellow through orange and red to blue, and also by the 
wav small ])articles of matte, slag and copper, wdiich are 
throW'ii up by the air blast, act when they strike the hood at 
the lower end of the flue into which the converter gas passes. 

The magnesia lining is one of the important recent im¬ 
provements in copper metallurgy. In former practice the ore, 
supplied to flux the iron of the matte, was ground together 
with some of the clay-like slime that is produced in the 
mechanical concentration process, and tamped into the shell 
for lining. Such lining was rapidly consumed and had to be 
frequently renewed. This resulted in much greater expense 
than with magnesia lining, which is not appreciably subject to 
fluxing though it does very gradually suffer by mechanical 
wear from the w^ash of the fluid charge. 

Unlike the slag from the reverberatories and blast fur¬ 
naces, that produced in the converting process is too rich in 
copper to be thrown away. Most of it, still liquid, is taken 
directly to a special reverberatory furnace in the converter 

Page Thirty-five 



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0 , 0 :: 

















building, Suitable amounts of calcine, dried concentrate 
and fine siliceous material are put into this furnace, to 
produce a final slag that retains so little copper that it can 
he sent to the dump. That portion of the converter slag that 
is sent hack to the blast furnaces is cast into slabs in a series 
of steel molds carried by a long chain conveyor, and allowed 
to solidify before being delivered to the stock bins. 

To take care of the frequent handling of large ladles 
and of the “boats’’ that are used to charge the ore, there are 
three very large and ])o\verful overhead travelling cranes, 
each equipped with electric motors, the operator riding in a 
cab that is hung on the crane. 


REFINING 

LTiiouGii the converters turn out the metallic cop¬ 
per, this product still contains small amounts of 
iron and sulphur, and also carries with it a little 
of the slag. These are removed in the refining 
furnaces, in which there is time and opportunity 
for more careful treatment than can be given in 
the converters. The refining furnaces are similar to rever¬ 
beratory smelting furnaces but of smaller size; and, like the 
latter, are heated with pulverized coal. 

When one of these furnaces has been charged wdth liquid 
copper from the converters, the end of an iron pipe, carry¬ 
ing air under a pressure of sixteen pounds per square inch, is 
depressed below the surface of the bath. This air burns out 
the remaining iron and sulphur, the former entering the slag 
and the latter passing away with the furnace gases. From a 
two hundred ton charge of metal three tons of slag is scraped 
out of the furnace. This is rich in copper and is returned to 
the converters. 

During the process of air refining more or less of the 
copper is oxidized, and considerable of this oxide dissolves 
in the bath. It is brought back to the metallic state by the 
reducing action of wood, the ends of green poles being 
forcibly held beneath the surface of the charge. The refiner 

Page Thirty-seven 






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C -it' 
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y a 
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(letermines when the copper has come to tlie right ‘^pitch" by 
observing the form of the surface of small cooled samples 
'which he takes in a little iron cup. 

Wdien the refining is completed, the copper is tapped 
from the furnace into cast iron molds which are carried on 
a chain conveyor and which form the metal into anodes. 
These are cooled in a tank of running water, loaded directiv 
into freight cars and sent to the Company's electrolytic 
plants where the silver and gold are separated. 

^ ^ » 

DUST CHAMBERS, FLUES AND STACK 

LL FURNACE DEPARTMENTS are Subjcct tO SOIUC loSS 

in the form of dust carried out bv the draft. This 
dust amounts to only a very small percentage of 
the material treated; vet it carries considerable 
metal value. From most of the departments the 
dust-bearing gases pass directly into brick cham¬ 
bers so large that the coarser particles settle. These cham¬ 
bers are elevated above ground level, and the bottom is made 
up of a large number of steel hoppers from which the dust 
is drawn into cars and delivered to the reverberatory furnaces. 

From the chambers the hot furnace gases pass through 
brick flues, most of wdiich are twenty feet wide and fifteen 
feet deep. Altogether there is nearly a mile of flues of this 
size; and the}^ all discharge into a main flue through which 
the smoke travels another half mile up the hill to the stack. 
ITr half its length this main carrier is sixty feet wide with 
walls rising twenty feet above the ground and with a V- 
shaped bottom extending seventeen feet into the ground. 
Still more dust settles in this large space, and is drawn 
through bottom gates into cars that run in a tunnel. The last 
half of this flue is one hundred and twenty feet wide and has 
a \\^-shaped bottom below ground, with two tunnels for dis- 
charp-ing the excessivelv fine dust that settles here. This 
dust also is delivered to the reverberatory furnaces. 

The flue gases finally discharge into the atmosphere 
through a stack which is built of perforated brick laid in 

Page Thirty-nine 





acid-resisting mortar, and has numerous 1)uilt-in bands of 
heavy reinforcing steel. Tt rests on a massive concrete 
foundation, towers five hundred and eighty-five feet above 
the ground and has an inside diameter of seventy-five feet 
at the bottom and sixty feet at the top, with walls varying 
from six feet thick at the base to two feet at the top. It has 
only recently been erected, being made necessary by the con¬ 
tinued increase in capacity of the W^orks during the past 
few years, and has taken the place of an older one that is 
thirty feet inside diameter and three hundred feet high and 
which was the largest among large chimneys when it was built. 
The new one in its turn is now the premier among such 
structures, and makes the first seem very small by comparison. 
This comparison well illustrates the fact that any object is 
“large'" or “small" only by contrast with something of 
strikingly different size. The new chimney has six times 
the carrying capacity of the old and can easily discharge three 
or four million cubic feet of gas per minute. 

A little fume escapes into the stack from the electrical 
precipitation process that is described later. Some of this 
escaping fume naturally sticks to the walls of the stack and, 
after a while, falls to the bottom in lumps. The bottom is 
concreted and made of hopper shape ; and when any consider¬ 
able quantity of dust has accumulated it is drawn off through 
gates into small cars. 

The gases from some of the furnace departments rise 
a thousand feet in their passage through the flue svstem, 
before leaving the top of the new stack, with a total travel of 
more than seven-eighths of a mile. 


Page Forty 


ELECTRICAL DUST PRECIPITATION AND 
ARSENIC RECOJ^ERY 


RACTioxAL PERCENTAGES of zinc aiicl ai'scnic occur 
in the copper ores; and these are largely vaporized 
as oxides during the various furnace operations. 
Leakage of cold air, and more or less loss of heat 
by radiation while passing through the flues, cause 
the condensation of a good deal of this vapor. 
Part of the resulting fume settles in all of the dust chambers 
and flues: but some of it passes through the entire flue system 
together with a small amount of the extremely fine dust that 
comes from mechanical attrition. During the past few years 
the Company has spent a good deal of money in experiment¬ 
ing with the Cottrell method of electrical precipitation to 
recover this excessively fine material; and four Cottrell units 
have been in successful operation for three years on the gases 
that come from number two roaster plant, where the very fine 
flotation concentrate is treated. The zinc roasting furnaces 
receive very fine feed, and it is necessary to use this method 
to control their dust losses also. In this case the conditions 
in regard to available space make it most convenient to have 
a small unit just above each furnace, through which the gas 
passes on its way to the flue. The precipitated dust drops 
back into the furnace. 

The experience with this method has been so satisfactory 
that twenty units have been installed to treat all of the 
gases just before they enter the new stack. The particular 
design of treaters in use here is the box type, so-called to 
distinguish it from the pipe treaters used elsewhere. Each of 
these box units is a rectangular chamber measuring nearly 
twentv-five feet in each direction. Sheets of corrugated 
roofing steel twenty-one feet wide and twenty-four feet high 
are hung vertically in these chambers, twelve inches apart; 
and, between the sheets, rows of small chains are suspended 
at five-inch intervals. The chains carry a static charge of 
electricitv at a tension of sixty-two thousand volts; and as 
the gases rise between the plates the particles of dust and 



Page Forty-one 





Coal Pulverizing Plant 


































































fume become electrically charged and are then repelled from 
the chains to the ]dates. The particles discharge their elec¬ 
tricity throngh the plates, which are connected to the earth, 
and the dust then collects into masses that are large enough to 
fall throngh the rising current of gas, and drops into hoppers 
at the bottom of the chamber. From these hoppers the prod¬ 
uct is trammed to a special reverberatory furnace near the 
treaters, and smelted in mixture with other suitable materials. 
Of the arsenic contained in this mixture a large part is vola¬ 
tilized in the furnace and carried by the hot gases through a 
special set of treaters, in which any dust is separated, while 
the arsenic, still in the gaseous state, passes on to a flue. Cold 
air is admitted to this flue, thereby condensing the arsenic, 
which is recovered in a second special set of treaters as a 
marketable product. From here the gas passes into the main 
stack. 

SUPPLIES 


Pud: All of the furnace operations, of course, reciuire 
much heat. In roasting the co])per concentrate, heat is obtained 
by combustion of the iron and sul])hur of the charge, as 
already indicated. This is true in the converters also, where 
a melting tem])erature is re(|uired; and in the l)last furnaces 
])art of the heat is obtained in this way. The latter furnaces, 
however, consume more than five hundred tons of coke every 
twenty-four hours when running at full capacity. Reverbera¬ 
tory smelting recjuires more than seven hundred tons of coal 


per day, and the steam boilers in the power houses use an 
average of fifty tons. Pulverizing the reverberatory coal is 
an important and interesting operation and requires an 
elaborate plant. The run-of-mine coal is first broken to a 
maximum size of an inch and a quarter by toothed rolls and 
is then taken by a system of elevators and a belt conveyor 
to a set of rotary driers, which reduce the seven or eight per 
cent of moisture to two per cent. This is done because the 


higher i)ercentage would make the coal clog in the pulverizing 
mills which follow. The discharge pulley of the conveyor belt 
is magnetic and takes out spikes and other ])ieces of iron and 


Page F'orty-three 



Brtck- Yard 




















steel which would damage the pulverizers. The final grind¬ 
ing is done in Raymond roller mills, in which the coal is 
constantly thrown between the die ring and the rapidly re¬ 
volving rollers. A centrifugal fan induces a circulation of 
air which enters through a series of openings in the bottom of 
the mill and passes out through a central pipe above and then 
on through the fan, the velocity being regulated to carry 
along only such particles of coal as have been reduced to 
sizes ranging from seven thousandths of an inch in diameter 
to the very finest dust. This product is se])arated from the 
air stream in a centrifugal dust catcher and is then carried to 


the bins above the reverberatory furnaces by a system of 
enclosed screw conveyors. 

Fhix: The limerock, used in both reverberatory and blast 
furnace smelting to make the slags more fusible, is quarried 
eight miles from the Works. It is suitable for blast furnace 
use just as it comes from the quarry, but for the reverbera- 
tories it is first crushed to one inch and smaller in diameter. 
The normal consumption at the reverberatories is three hun¬ 
dred tons a dav; and when the blast furnaces are in full 
operation they use a thousand tons a day. 

Fire and Building Bricks: In the roasting furnaces the 
heat is so moderate that a good grade of clay brick is suffi¬ 
cient; but in reverberatory smelting the temperatures are as 
high as twenty-eight hundred degrees Fahrenheit, and only 
very high grade silica brick will give good service. Such bricks 
are made at the Company's brick-yard situated near the Re¬ 
duction Works, using rock that is obtained but a few miles 
away. Magnesite, brought from the State of Washington, 
is used to produce basic bricks for converter lining; and fire 
clav bricks are made from a mixture of local clay and a clay 


shipped from a distance of two hundred miles. 

All of the building bricks used about the Works are made 
from a mixture of the sandy and the slime portions of the 
tailing from the copper concentrator, the slimy part being- 
in the nature of clay. These are burned in a semi-continuous 
kiln shown under the long roof in the illustration. Just be- 
vond and in line with this are the bee-hive kilns in which the 
other three kinds of bricks are burned. 


Page Forty-five 



Sulfhuiic Acid Plant 






































Sulphuric Acid: To supply the needs of the flotation 
process and of the leaching- department for acid there is a 
sulphuric acid manufacturing plant just below.the hill. For 
raw material this plant uses some of the fine concentrate, 
which is roasted in McDougall furnaces. The resulting gases 
are passed through special dust se])arators, and then through 
the Glover towers in which they come in contact with a mix¬ 
ture of sulphuric and nitric acids. These towers are octag¬ 
onal lead chambers lined with brick, about fifty feet high and 
fifteen feet inside diameter. They are filled with a loose 
checker work of brick over which the acid mixture falls in 
thin layers and so comes into intimate contact with the rising 
gases. The conditions as to temperature and dilution of the 
acid are such that the nitric acid is vaporized and carried 
along into a series of lead chambers each enclosing a space 
of a hundred and thirtv thousand cubic feet. Steam and 
finely divided water spray are blown into these chambers. 
The sulphur dioxide is changed to sulphur trioxide by the 
action of the nitric acid and the excess oxygen of the furnace 
gases, and the sulphur trioxide combines with the water 
vapor to form the sulphuric acid. After leaving the chambers 
the spent gases are passed through Gay-Lussac towers in 
order to recover the nitric gas by bringing it into contact 
with strong, cold suljdiuric acid which dri])s over a checker 
work of brick. The reason that the nitric gas is absorbed here 
while it is vaporized in the Glover to^vers is that conditions of 
temperature and acid strength are very different in the two 
cases. The i)roduct of the Gay-Lussac towers is used again 
in the Glovers. 

A recent addition to the ])lant embodies the latest de¬ 
velopments and a radical improvement in acid manufacture, 
consisting in the sul)Stitution of relatively small brick-])acked 
towers in place of the immense chambers that are used in 
common ])ractice. This tower installation is seen at the left 
of the op])Osite picture, with an outside stairway leading to 
the upper ])art of it. The brick building in the center con¬ 
tains the roasters and dust catchers for both the chamber 
and the tower processes; while the large brick building, at 
the right, houses i)art of the chamber system. A ])lant of 

Page Forty-seven 


the tower type can be erected for forty to fifty per cent of 
the cost of a well-built chamber plant of the same capacity, 
and requires only twenty to twenty-five per cent as much 
ground area. Operating costs of the two types are about 
equal, although for small tonnages they may be somewhat less 
in a chamber plant. 

Water and Compressed Air: An abundant water supply 
is one of the most important needs of an ore reduction 
works; and it was this that led to the selection of 
Anaconda as the site of the Company’s original treatment 
plant. The present consumption of water exceeds sixty 
million gallons in twenty-four hours. The concentrator uses 
three-fourths of the supply; but sixty per cent of what it 
uses is recovered to operate the steam condensers in the 
power house, to sluice slag and for other purposes. The 
leaching plant and the smelting departments use fifteen million 
gallons of fresh water, to dissolve copper from the old tailing, 
to make steam and for different cooling operations. The 
supply, which comes from a watershed within twenty miles 
of Anaconda, is diverted from Warm Springs creek into a 
wooden flume that follows the hillsides for a distance of eight 
miles. 

Compressed air is as important as water, and is used in 
numerous ways. The volume, before compressing, of the air 
required in twenty-four hours when the plant is in full opera¬ 
tion is nearly five hundred million cubic feet and weighs 
sixteen thousand tons. It is distributed as follows: 


Pounds pressure 

per square inch. Cubic feet. Tons. 

Blast furnaces . 2^^ 300,000,000 9,700 

Converters . 16 100,000,000 3,200 

Reverberatories . 1 70,000,000 2,300 

General mechanical use.... SIO 18,000,000 580 

Air locomotives .900 7,000,000 230 


The ninety-pound air is used to raise gates on bins and 
furnaces, to operate air tools and for miscellaneous mechanical 
purposes. 


Page Forty-eight 






POIVER AND TRANSPORTATION 


N SUCH A PLANT as this the power consumption is 
necessarily great. Twenty thousand electric 
horse-power is received from the water-power 
plants of the Montana Power Company. This 
comes in with an electrical pressure of ninety-two 
thousand volts, and is transformed to twenty-two 
hundred volts, at which it is used in the larger motors. The 
opposite illustration shows some of the switch-boards, and 
also powerful motors operated by high voltage current and 
driving generators that deliver current at lower voltage. 

Another ten thousand horse-power is developed in steam 
engines. Eighty per cent of the steam comes from the waste- 
heat boilers that are attached to the reverberatory furnaces. 

Fifteen thousand horse-power is used to compress air 
in the main power house. T3ifferent types of compressors are 
used for the different pressures. There is one turbo blower 
operated by a steam turbine, and another driven by an electric 
motor, and these are the most modern type of air compress¬ 
ing machinery. Their particular merit is that they require 
much less floor space than is needed for other types. Although 
running at thirty-six hundred revolutions a minute they are 
so nicely built that there is no perceptible tremor in any part 
of the machines. There are also numerous reciprocating 
piston compressors for the higher air pressures, and rotary 
blowers for the two-and-a-half pounds pressure used in the 
blast furnaces. 

The other large consumer of power is the concentration 
process, which requires twelve thousand horse-power. 

For the transportation of various products from one de¬ 
partment to another there are fifteen miles of standard gauge 
track over which the trains of the local tramming system are 
moved by twenty-one compressed air locomotives and two 
steam locomotives that burn fuel oil. This service uses three 
hundred and twenty-five cars, and carries seventeen to 
eighteen thousand tons of total material a day. 

There are also a number of belt conveyors, delivering 
])art of the concentrate to the roasting furnaces. 

Page Forty-nine 







Motor-Generator Sets and Switchboards in Electric Sub-Station 




























Local Tram Train, and General Office 

























CONTROL AND DEVELOPMENT OP PROCESSES 


o MAKE THE WORK of the entire plant successful 
every department must he kept up to a high 
standard of results; and this requires constant 
watchfulness. There is separate metallurgical 
accounting for each of the departments as strict as 
if they were owned by different companies. All 
of the material entering and leaving any department is care¬ 
fully weighed on track scales, and there is an elaborate plan 
of sampling. All samples after proper preparation are de¬ 
livered to the chemical laboratories where determinations are 
made not only of copper, silver and gold but also of silica, 
iron, alumina, lime, sulphur, arsenic, etc., as well as the quality 
of coal, of oil and of other supplies. In the course of a month 
the laboratories receive sixty-five hundred samples and make 
more than sixteen thousand chemical determinations. 

There is also a testing department which inquires into 
special conditions in the operating departments to locate the 
cause of unusual results and to indicate remedies. This de¬ 
partment also makes physical tests of construction materials. 

The research department conducts numerous and ex¬ 
tended investigations for the improvement of processes and 
for the development of new lines of commercial work. It is 
well equipped for both preliminary tests and small scale 
operating tests in concentration, leaching, electrolytic precipi¬ 
tation and electric smelting. 

The most notable of the improvements and new metal¬ 
lurgical methods that have been adopted by the Companv 
in recent years are the flotation process, the use of pulverized 
coal in reverberatory furnaces, basic converter lining, the 
electrical method of dust settling, and the electrolytic process 
of zinc extraction. These have required a good deal of in¬ 
vestigation by the research, chemical and testing departments, 
beside much knowledge and skill on the part of the mechanical 
and civil engineering departments in designing, laying out 
and constructing new buildings and equipment. 



Page Fifty-two 




THE HUMAN SIDE 


Personnel. Visitors remark that comparatively few men ' 
are in evidence about the plant, most of the work being done 
by mechanical power. This is true; and such large scale 
production would be almost impossible without modern 
mechanical methods; but machines and furnaces have neither 
brains nor personality, they cannot run themselves, and the 
success of the whole enterprise depends on three human 
factors. There must first be careful and well considered 
planning in order to make all of the human, the metallurgical 
and the mechanical factors work together. Lack of this would 
make all industry like a mariner without a chart. Then, to 
provide the managing staff with the necessary information 
for this planning and for supervision there are both regular 
and special investigations by the accounting and technical 
staffs. Finally, for the actual control of machinery and 
processes, there is the intelligent interest and skill of many 
experienced millmen,^ furnacemen and mechanics. There are 
in fact more men employed at the Works than a casual visitor 
appreciates. The best impression as to their number is to be 
had when they check in or out at the timekeeper's office. The 
picture on the opposite page shows a thousand men gather¬ 
ing at the close of a day’s work. All told, there are twenty- 
seven hundred employes, sixty per cent of whom are directly 
eno-agfed in treating- the ore. In the total number there are 
three hundred and fifty carpenters, metal trades workers, 
electricians, masons and painters, who keep the plant in good 
repair; one hundred men in the power houses; one hundred 
and fifty in the transportation service; and two hundred in 
what is called the surface crew, who take care of various lines 
of work both outside of and in assistance to the operating de¬ 
partments, such as moving machinery and supplies, excavat¬ 
ing for construction and renewals, disposing of slag and main¬ 
taining an orderly condition of the plant. The force also 
includes a technical staff of sixty metallurgists, chemists, 
mechanical, civil and electrical engineers and draftsmen, 
occupying three sizeable brick buildings, one of which is 
shared with the accounting department. The latter includes 


Page Fifty-three 



The Human Side 

































one hundred men and women who take care of the Company’s 
i>'eneral accounting for mines and sn])sidiary interests as well 
as of the local records of the Reduction Works. The offices 
of the general managing staff are also in this building, which 
is thus the center of snj^ervision and direction for all opera¬ 
tions in the entire Works. The supervising force consists of 
two hundred and forty men, from general manager through 
general and departmental superintendents to shift foremen 
and eang bosses. 


Sajiifafion. For the convenience and comfort of the 
men there are several change houses containing individual 
lockers in which to keep street clothing wFile at wmrk and 
working clothes at other times ; also Avash sinks with hot and 
cold w^ater faucets, well equipped showier baths and toilet 
rooms. Tn all of the Iniildings there are sanitary drinking 
fountains. 

Safety and First Aid. To minimize accidents there is 
a tvell organized department of safety, under the oversight of 
a safety engineer wdto gives all of his time to this work and 
who is responsible to a general safety committee. Each oper¬ 
ating department has a committee, comprised of its superin¬ 
tendent and a number of the foremen and workmen. The 
members of these committees take personal interest in guard¬ 
ing their fellows against dangerous practices, and in suggest¬ 
ing safety devices and methods to the general committee. All 
suggestions, if found feasible, are promptly put into effect. 
Attractive periodical bulletins, of both cautionary and educa¬ 
tional character, mostly ])nblished by the National Safety 
Council, are posted in all of the operating departments. The 
Anaconda Company ])nhlishes '‘The Anode A a small monthly 
masrazine devoted to safetv and first aid, wdiich is distributed 
to all employes at the mines, reduction w’orks and elsewdiere. 
There has come to he a good spirit of co-operation between 
the members of the departmental safety committees and the 
safety engineer. Even before this work w^as organized the 
record as to accidents was a good one in comparison with 
many industrial establishments, because the plant and equip¬ 
ment w^ere laid out to avoid dangerous situations. An excel- 


Page Fifty-five 


(ent illustration of the fact that even in this distinctly 
machinery age the human element is, after all, the most im¬ 
portant, is found in the record of injuries. This record shows 
that accidents happen by far most often among men who 
are juitting in their first shift in unfamiliar ])laces, and are 
hurt either because someone else neglects to point out or to 
remove the dangers or because they are themselves careless 
about noticing danger. Although mechanical safeguards 
should be and are provided in abundance, it yet remains true 
that “the best safety device known is a careful man.” Both 
for the benefit of his fellows and for his own sake every man 
ought to cultivate the habit of watchfulness, take the trouble 
to “go the other way round” and use care at all times. This 
does not mean loitering, but in the end saves time, gets more 
and better results and leaves everybody better off and more 
satisfied. Such self discipline is of great benefit in various 
other ways as well as in promoting safety while at work. 

In the five years since the Company organized its safety 
work, it has spent more than a hundred thousand dollars in 
Anaconda to provide safeguards and to help the men “get 
the habit.” Twice this amount has been expended at the 
mines in Butte ; and when the Great Falls plant, the coal mines 
and lumber mills are included the total expenditure for the 
five years exceeds half a million dollars. 

When accidents do occur, prompt care is given by a 
trained nurse; and the employes are constantly urged to have 
even minor accidents, such as a cut finger or dust in the 
eye, attended to at once. This they very generally do, and so 
avoid prolonged inconvenience and the possibility of danger¬ 
ous infection. If the case is a serious one the patient is taken 
home or to the hospital, in the city, in a motor ambulance 
which is provided with the best obtainable equipment. Beside 
the chief nurse there are three other men in this service, so 
'that each eight-hour shift is provided for. This work is all 
at the expense of the Company ; but each em]doye pays a 
dollar a month to an inde])endent institution which i)rovides 
for ordinary hos])ital i)rivileges and for any necessarv atten¬ 
tion from a staff of idiysicians. 


Page Fifty-six 




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